Split the lttng-tools wrapper in a separate artifact

[lttng-ust-java-tests.git] / lttng-tools-java / src / main / java / org / lttng / tools / utils / ShellUtils.java

diff --git a/lttng-tools-java/src/main/java/org/lttng/tools/utils/ShellUtils.java b/lttng-tools-java/src/main/java/org/lttng/tools/utils/ShellUtils.java
new file mode 100644 (file)
index 0000000..eb94c20
--- /dev/null
+++ b/lttng-tools-java/src/main/java/org/lttng/tools/utils/ShellUtils.java
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2015, EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+package org.lttng.tools.utils;
+
+import java.io.IOException;
+import java.lang.ProcessBuilder.Redirect;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.StringJoiner;
+
+/**
+ * Utility methods to execute commands on the command line.
+ *
+ * @author Alexandre Montplaisir
+ */
+public final class ShellUtils {
+
+    private ShellUtils() {}
+
+    /**
+     * Simple command to test that the environment / stdout are working
+     * correctly.
+     *
+     * @param args
+     *            Command-line arguments
+     */
+    public static void main(String[] args) {
+        List<String> command = Arrays.asList("ls", "-l");
+        executeCommand(command);
+    }
+
+    /**
+     * Execute a shell command and retrieve its return value.
+     *
+     * @param command
+     *            The command to execute, as a list of individual arguments (do
+     *            not use spaces)
+     * @return If the command returned successfully (ret code = 0)
+     */
+    public static boolean executeCommand(List<String> command) {
+        try {
+            /* "echo" the command to stdout */
+            StringJoiner sj = new StringJoiner(" ", "$ ", "");
+            command.stream().forEach(sj::add);
+            System.out.println(sj.toString());
+
+            ProcessBuilder builder = new ProcessBuilder(command);
+            builder.redirectErrorStream(true);
+            builder.redirectOutput(Redirect.INHERIT);
+
+            Process p = builder.start();
+            int ret = p.waitFor();
+
+            System.out.println("(returned from command)");
+
+            return (ret == 0);
+
+        } catch (IOException | InterruptedException e) {
+            return false;
+        }
+    }
+
+    /**
+     * Execute a shell command and retrieve its output.
+     *
+     * @param print
+     *            Should the output also be printed to stdout as usual
+     * @param command
+     *            The command to execute, as a list of individual arguments (do
+     *            not use spaces)
+     * @return The output of the command, as one list element per line
+     */
+    public static List<String> getOutputFromCommand(boolean print, List<String> command) {
+        try {
+            /* "echo" the command to stdout */
+            StringJoiner sj = new StringJoiner(" ", "$ ", "");
+            command.stream().forEach(sj::add);
+            System.out.println(sj.toString());
+
+            Path tempFile = Files.createTempFile("test-output", null);
+
+            ProcessBuilder builder = new ProcessBuilder(command);
+            builder.redirectErrorStream(true);
+            builder.redirectOutput(Redirect.to(tempFile.toFile()));
+
+            Process p = builder.start();
+            p.waitFor();
+
+            List<String> lines = Files.readAllLines(tempFile);
+            Files.delete(tempFile);
+
+            if (print) {
+                /* Also print the output to the console */
+                lines.stream().forEach(System.out::println);
+            } else {
+                System.out.println("(output silenced)");
+            }
+
+            System.out.println("(returned from command)");
+            return lines;
+
+        } catch (IOException | InterruptedException e) {
+            return null;
+        }
+    }
+}